What is the equation of the vertical asymptote of f(x) = (2x+9)/(x-4)?

The vertical asymptote of a rational function occurs where the denominator is zero and the numerator is nonzero. Set $x - 4 = 0$ to get $x = 4$. The numerator there is $2(4) + 9 = 17$, which is not zero, so there is a vertical asymptote at $x = 4$, choice B. Choice A ($x = -4$) has the wrong sign. Choice C ($x = 9$) uses the constant term of the numerator. Choice D ($y = 2$) is the horizontal asymptote, the ratio of leading coefficients, and is not vertical.